For example, Document EP-A-0124185 discloses a press comprising a table provided with four pillars supporting a crosshead at their top ends, which crosshead forms the main cylinder for a ram piston and supports two control actuators for raising and lowering a skirt that is lowered to cover the drum to be compressed when said drum is deposited on a pressing block situated on the table. During compression, the ram penetrates into the skirt which thus protects the drum. Once the drum has been compressed, the ram piston is raised again, as is the skirt which is retracted up inside the cylinder of the ram piston while surrounding the ram. The ram piston is in turn provided with a non-through bore which acts as a cylinder for a fixed piston secured to the top end of the main cylinder. This makes it possible to exert "low thrust" during a first stage of the press stroke by feeding the chamber situated beneath the fixed piston and whose cross-sectional area is small, and to exert higher thrust during a second stage of the press stroke by feeding the chamber situated above the ram piston and whose cross-sectional area corresponds to the entire cross-sectional area of the main cylinder.
Such a press therefore includes two actuators for the skirt, in addition to the ram piston which cooperates with the fixed piston to form a compound actuator.